|Publication number||US8012432 B2|
|Application number||US 11/493,697|
|Publication date||Sep 6, 2011|
|Filing date||Jul 27, 2006|
|Priority date||Nov 21, 2001|
|Also published as||EP1459047A1, EP2241871A1, US7335339, US20040213699, US20060263246, WO2003044488A1|
|Publication number||11493697, 493697, US 8012432 B2, US 8012432B2, US-B2-8012432, US8012432 B2, US8012432B2|
|Original Assignee||Boule Medical Ab|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (16), Classifications (19), Legal Events (2)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The present application is a Continuation of Application Ser. No. 10/849,239, filed May 20, 2004, now U.S. Pat. No. 7,335,339 and claims priority under 35 U.S.C. §119 to Swedish Patent Application No. 2001-0103877-7, filed Nov. 21, 2001, the entire contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention concerns a disposable apparatus for use in blood testing.
2. Description of Background Art
When making blood tests in the field, it is a desire to perform such tests with simple but reliable apparatus that can be handled even by relatively untrained personnel. Still, there exists the requirement that a blood sample shall be taken and handled under strict hygienic conditions, and that neither the sample itself or residues thereof, nor diluting or flushing liquids used when testing the sample shall risk to be contacted by humans. Thus, there shall be no waste matter and all contaminated material shall remain within the apparatus.
It is known in the state of art to count blood cells by causing a volume of diluted blood sample to pass a so-called capillary, i.e., an extremely small hole, generally in a ruby, the hole having a diameter considerably larger than the size of a blood cell, typically 80 μm. A voltage is applied over the capillary, and, when a blood cell passes through the hole, the electrical resistance changes. This is because the cells can be regarded as insulators. Each change in resistance can be detected by suitable electronic equipment, and the sum of all changes detected corresponds to the number of blood cells having passed through the capillary. In order to obtain the concentration of cells in the original sample, the concentration of cells in the diluted sample is multiplied by the dilution factor, typically 1:40000 when counting of red blood cells (RBC) is concerned. It is obvious, that measuring of sample volumes and dilution liquid volumes must be performed in an accurate and repeatable way such that not only a correct degree of dilution can always be guaranteed but also a thorough and uniform mixing of the two volumes is ensured.
A disposable sampling device for an apparatus for counting particles contained in a liquid, such as blood cells in a blood sample, is known from WO 99/01742. This device is capable of making one diluting step.
A blood testing apparatus for performing dilution of a small defined volume of blood sample contained in a capillary tube is described in U.S. Pat. No. 6,284,548. The dilution involves a pre-dilution step and a final dilution step.
A device for diluting and mixing a liquid sample, such as a blood sample for performing a CRP test, is described in WO 01/75416. The sample is contained in a capillary tube and is mixed in a first step with a diluting agent to provide a diluted sample. In a second step, a third medium, such as antibodies, may be mixed with the diluted sample.
Even if some of the prior art devices are capable of making two dilutions, none of them is capable of making two simultaneous dilutions to different dilution ratios, which is desirable in order to perform, e.g., simultaneous counting of white and red blood cells.
It is a main object of the present invention, thus, to provide a disposable apparatus for use in blood testing, which allows simultaneous dilution of a blood sample to two defined dilutions ratios. Also, in order to avoid waste, the disposable apparatus shall be capable of retaining all contaminated material within itself. It is also an object of the present invention to propose an instrument for use with the apparatus.
To fulfill the main object above, the present invention proposes a disposable apparatus for use in blood testing and being adapted for simultaneous dilution of a blood sample into two different dilution ratios, said apparatus including a block-shaped housing having integrated therein: a first and a second receptacle, one of which, as a first blood sample receiver, being adapted to receive a blood sample; a first and a second container, each containing a defined volume of a diluting agent; a valve including a valve body having three valve body channels extending therethrough and being positionable in three distinct positions, one of which bringing the receptacles in simultaneous communication with a respective one of the containers through pairs of the channels; and displacers for displacing the diluting agent and the diluted sample through said channels between said containers and said receptacles. The displacers may be pistons movable in cylinders provided in the housing, or, an external source of pressure may be utilized to displace the diluting agent and the diluted sample.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
The invention will now be described in connection with an embodiment thereof utilizing a turning valve, and pistons as displacers, reference being made to the accompanying schematic drawings, wherein:
It is evident for the skilled person that the present invention may as well be practiced utilizing a sliding valve instead of the turning valve specifically described. I the following description, the terms upper, lower, right, left etc., refer to the position of the apparatus shown in the various Figures.
The overall structure of the apparatus will first be described with reference to
In a central portion of the housing is provided a cylindrical hole 8. Two channels 9 and 10 extending towards the upper end 2 open in the hole 8 at spaced locations along its upper circumference. Correspondingly, two channels 11 and 12 extending towards the bottom end 3 open in the hole 8 at spaced locations along its lower circumference.
A turning valve body 13 dimensioned to fit into the hole 8 is placed therein so as to be rotatable between at least three distinct positions. Three separate channels, a first channel 14, a second channel 15 and a third channel 16, extend through the valve body between mutually diametrically opposed positions along the circumference of the valve body. The channels are angularly spaced such that there is a substantially 60° angular distance between them along the circumference. By turning the valve body, the channels 14-16 may be positioned so as to cross-wise put the channels 9/12 and 10/11 in communication with one another.
The valve body is shown in
In the upper portion of the housing 1 are formed two receptacles 19, 20, preferably formed like parallel bores. A first one of these, receptacle 19, has its lower end 19′ connected to the channel 9. Its upper end is shown to be closed, but it may as well be open and closed by any suitable removable cover. A second one of the receptacles, receptacle 20, has its lower end 20′ connected to the channel 10. Its upper end is closed by a preferably circular cover 21 snapped into engagement with a hook-like protrusion 22 formed at the upper end 2 of the housing.
The cover 21 is shown to carry a capillary tube 23 having an upper end 24 and a lower end 25. The tube is mounted in the cover by means of ribs 26 depending from the cover such that the upper end of the tube opens in an open space between the ribs communication with atmosphere.
As an alternative option, there may be provided a separate cover 21 to close the receptacle 20 and a separate combination of a cover 21 and a capillary tube as shown.
In the lower portion of the housing 1 are formed two parallel cylinders 27, 28. A first one of these, cylinder 27, has its upper end 27′ connected to the channel 11. A second of the cylinders 28 has its upper end 28′ connected to the channel 12. A first piston 29 is slidably reciprocatingly movable along the cylinder 27. A second piston 30 is slidably reciprocatingly movable along the cylinder 28. The pistons have piston rods 29′, 30′, respectively, each having in a lower end thereof a through hole 29″, 30″, respectively. The holes 29″, 30″ are accessible through vertically extending apertures 7′ in the rear wall 7 of the housing.
The right hand wall 5 of the housing is provided with a cylindrical protrusion 31, in the centre of which opens the channel 18 with a slightly widening mouth portion 18′. An elastic diaphragm 32 seals the mouth portion 18′. In the preparatory state of the apparatus, the cylinders 27 and 28 are both filled with well-defined volumes, typically 2 ml, of diluting agent D1, D2, respectively, typically isotonic sodium chloride solution. Furthermore, the channel 16 is filled with an appropriate amount of a haemolysis agent H, which may be in a dried or a fluid state. In the first position I of the valve body 13, where the ends of the channel 16 are located at a distance from any one of the housing channels 9, 12, 17, 18, the haemolysis agent H is effectively prevented from escaping the channel 16.
In a first mode of operation shown in
In the state according to
In a second mode of operation shown in
In the state according to
It is noted in
Turning now to
As shown in
In the second mode of operation, an upward stroke of piston 29 will displace the diluting agent D1 through the channel 14 and consequently bring along the defined volume of sample S contained within the channel 14 directly into the recipient 20 in case there is no capillary tube 23 present, and partly through such tube if one is present. Subsequent strokes according to arrow P will complete the first stage mixing operation as in the first mode of operation.
In a following step, the turning valve is rotated counterclockwise to its third position III, where its channel 14 connects channels 9 and 12, and its channel 16 connects the channels 10 and 11 (
Upward movement of the piston 29 as shown in
After this final dilution step, the measurements on the two differently diluted samples (S+D1+H) and (S+D1+D2) are performed with the instrument mentioned. Apart from its operating arms, the instrument includes a measuring system having means for conducting at least parts of the contents in the receptacles 19 and 20 past measurement stations, where particle counting is performed, as well as means for controlling the volumes to be measured and means for flushing the various conduits of the measuring system. Such means are shown in
The measuring system includes two similar conduit branches 45 a, 45 b, one for each of the receptacles 19, 20. Each such branch starts with a needle portion 46 a, 46 b directed in parallel with the arms 38-41 so as to pierce corresponding diaphragms 47 a, 47 b sealing apertures 48 a, 48 b in the rear housing wall 7 communicating with the receptacles 19, 20, respectively.
The needle portions are in fluid communication with conduits 49 a, 49 b. These are provided with cell counting stations 50 a, 50 b, each comprising a first electrode 51 a, 51 b, an orifice 52 a, 52 b and a second electrode 53 a, 53 b. The orifices are small apertures allowing statistically only one blood cell to pass at a time. By means of electric wires 54 a, 55 a and 54 b, 55 b, respectively, a voltage may be applied over the orifices, and any change in the resistance between the electrodes, indicating the passage of a blood cell to be counted, may be detected by suitable electronic equipment included in the instrument, and the sum of all resistance changes detected corresponds to the number of blood cells having passed through the orifice.
Each of the conduits 49 a, 49 b is branched into two sub-branch conduits 56 a, 56 b and 57 a, 57 b, respectively. The conduits 56 a, 56 b lead to a respective container 58 a, 58 b containing a flush liquid F. The flush liquid also fills the conduits 56 a, 56 b as well as the conduits 49 a, 49 b including the needle portions 47 a, 47 b. Valves 59 a, 59 b are mounted in the conduits 56 a, 56 b between the containers 58 a, 58 b and the sub-branch conduits 57 a, 57 b, respectively. Valves 60 a, 60 b are also mounted in the conduits 57 a, 57 b. The flush liquid F is filled into the conduits 56 a, 56 b to a level LF above the valves 60 a, 60 b.
Substantially vertical portions of the conduits 57 a, 57 b are provided with lower counting start detectors 61 a, 61 b and upper counting stop detectors 62 a, 62 b spaced defined distances.
After completing the simultaneous mixing operations described above with reference to
From these positions, the pistons are further displaced upwards to press the respective contents of the receptacles 19, 20 through the needle portions 46 a, 46 b and into the conduits 49 a, 49 b. During this process, the flush liquid contained within the needle portions and the conduits will be displaced through the conduits 49 a, 49 b, including the electrodes 51 a, 51 b, the orifices 52 a, 52 b and the electrodes 53 a, 53 b, through the open valves 60 a, 60 b to raise the original level LF towards the respective lower detector 61 a, 61 b.
It should be emphasised at this stage of the description, that the various conduits shown in the drawings are not drawn in proper relative scales. In practice, and as will be evident for the skilled person, the volumes within the conduits 49 a, 49 b, including the needle portions 47 a, 47 b, up to the second electrodes 53 a, 53 b, are at least equal to the volumes within the conduits 57 a, 57 b between the valves 60 a, 60 b and the counting start detectors 61 a, 61 b.
In other words, the dimensioning of the conduits is such, that when the levels of the flush liquid in the vertical conduits 57 a, 57 b have reached the counting start detectors 61 a, 61 b, the respective diluted sample shall at least have reached its associated second electrode 53 a, 53 b, respectively.
Thus, when the level of the flush liquid has reached the respective counting start detector 61 a, 61 b, a signal is delivered to the instrument to start particle counting, i.e., to start recording each resistance change detected over the electrodes 51 a, 53 a and 51 b, 53 b, respectively. As soon as the levels LF in the conduits 57 a, 57 b have reached the respective upper detector 62 a, 62 b, a stop counting signal is delivered to the instrument, and the corresponding results may be stored in the instrument and/or displayed on it.
During the counting process, the diluted blood samples never reach further along the conduits than to positions well before the respective branching point 49′ of the conduits 49 a, 49 b.
After the counting process has been completed, the pistons 29, 30 are returned to positions where the levels LF in the conduits 57 a, 57 b are substantially as before starting the counting.
At this stage, the valves 60 a, 60 b are closed, the valves 59 a, 59 b are opened, and the pistons 29, 30 are lowered to their bottom positions as shown in
In this position, all possibly contaminated liquid is contained within the cylinders 27, 28. When finally removing the disposable apparatus housing 1 from the instrument, the elastic diaphragms 47 a, 47 b will effectively wipe off any diluted sample residue from the needle portions 46 a, 46 b.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
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|U.S. Classification||422/547, 422/504, 422/565, 422/501|
|International Classification||G01N1/38, A61M39/22, B01L3/00|
|Cooperative Classification||B01L2400/065, G01N1/38, A61M39/223, Y10T436/25625, Y10T436/2575, B01L3/502, Y10T436/25, B01L2400/0478, B01L2400/0644, B01L2300/0645|
|European Classification||G01N1/38, B01L3/502|
|Nov 29, 2011||CC||Certificate of correction|
|Mar 5, 2015||FPAY||Fee payment|
Year of fee payment: 4